The overarching goal of the proposed Advanced Center to Improve Pediatric Mental Health Care (ACIPMHC) is to improve care for children with mental health problems by achieving greater integration of evidence-based practice in community care settings, particularly in the child welfare and mental health service sectors. The Research Methods Core (RMC) will contribute to this objective by developing innovative strategies to address emerging methodological challenges that arise in studies examining the effectiveness and implementation of innovative, evidence-based services. The work proposed in the RMC will be conducted by a network of experienced quantitative and qualitative methodologists from the principal CASRC and CR2P sites in San Diego and Eugene, and from two affiliated premier methods and statistics entities, the Center for Health Statistics (CHS) at the University of Illinois, Chicago (led by R. Gibbons) and the Prevention Science and Methodology Group (PSMG) at the University of South Florida (led by H. Brown). Within the broader ACIPMHC framework, the RMC has two specific aims. (1) To develop innovative strategies to address emerging methodological issues in effectiveness and implementation research, including: (a) design and analysis issues, including multi-level power, alternative randomized and non-randomized designs, and the impact of provider and provider organization turnover on analysis and interpretation;(b) measurement development, including estimates of intervention and implementation fidelity, and feasible measures of client-level mediators and outcomes for use in usual care settings;(c) use and integration of mixed methods in effectiveness and implementation research, and (d) economic analysis, including development of unit costing of child welfare services, and testing cost offset for parent management training interventions. (2) To provide methodological support for ACIPMHC investigators and their community partners in effectiveness and implementation research. To accomplish these aims, specific workgroups and projects have been established in each Aim 1 area. Support for ACIPMHC studies will occur through direct involvement of RMC investigators in ongoing and proposed studies, as illustrated by the cross-over of investigators between projects in each ACIPMHC core, and through work selected to address major methodological issues in research on the translation of evidence-based practices into the community.